Sound-conduit or amplifying device for talking-machines and the like.



A. PISGHEP.

SOUND COILIDUIT OR AMPLIFYING DEVICE FOR TALKING MACHINES AND THE LIKE.

APPLICATION FILED APR.18, 1910.

1,029,992,, Patented June 11, 1912 Unirnn snares rairnni L ALEX FISCHER, 'WEST KENSINGTQN, LONDON, ENGLAND.

SOUND-UQNDUIT matinee.

To all whore may concern:

Be itknown that 1. Anna hicnna, a sub ject of the King of England. residing at 8 Maelise road, West Kensington, in the county London, England, have invented certain new and useful Improvements in and Relating to Sound-Conduits or Amplitying Devices for 'lalking-Machines and the Like; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to sound conduits applicable to talking machines and the like in which one or more bends are formed for the purposeot directing the sound waves in the desired direction. and the object of invention is to so form the bends that. the sound waves may be passed ,through the conduit in straight lines without being compressed, intermingled or ditlused and without being deflected against the side walls of the conduit.

In carrying out my invention each joint or bend in the conduit is provided with a. reflecting surface which is inclined equally to the axes of both parts of the conduit on opposite sides of the bend so that the sound waves are reflected in straight lines'parallel with the axis of the conduit. The cross sectional. area of the conduit in the narrowest part of thc bend is approximately the same as the cross sectional area of that part of the conduit from which the rcticctor receives the sound waves whereby such waves are transmitted without compression or diffusion. The reflecting surface is of such size as to receive all ol the waves and directly transmit all ot them to the next part of the conduit. area of the conduit at the narrowest part of the bend is approximately the same as the cross sectional area of that part of the conduit whence the sound waves proceed. The section of the conduit will in most cases consequently and relatively increase in size from the receiving to the discharge end in order to obtain the advantages above specified. By the construction explained, sound waves are transmitted without compression, deflect-ion or diffusion, and these waves are discharged from the conduit with full volume of clear tone and of good quality.

In the accompanying drawings, Figure 1 shows a side elevation of a sound conduit .tLMPhIFYING DEVICE FOR TALKING-MACHINESAND If Specification of Letters Iiatent.

Apiilication filed April 16, 1910.

'lhe cross sectional Patented Jone Serial No. 555,??6.

witlrseveral bends made in accordance with my invention, such conduit being in this instance of suitable constriwtion for the tone arm of a talking machine. 2 is a plan view of part of the conduit shown in 1. Fig: 3 shows an elbow joint suitable for connecting a tone arm with a trumpet.

The tube (Z is adapted to connect with a sound box of a talking machine and it joins a tube (1 which arranged at an angle to the tube (.7. As shown, the axes of the two tubes are at an acute angle to each other. f is a reflecting surface between the two tubes. The tube e joins a tube of larger diameter and at it is a reflecting,- surface which receives sound waves from the tube 6 and transmits them through the tube 1' In Fig. 1 the outlines of the projected surface. '1'. e. the surface upon which the sound I to connect with the part at in Fig. and tlllS part p connects with a part o't larger diameter, there bcin; a reflecting surface r which receives all the sound waves passing out through 7) and transmits them through the part. (1. in each case the dian'i ier of the two parts of the conduit on opposite sides of any joint or bend are of such relative size and the reflecting surface is oi such proportions that the tree space at the narrowest place between the angle of the bend and the rellector is about equal to the diameter of the smaller part ol the conduit, 2'. 0., the part -from which the sound waves pass on their way to the bend. For instance. as shown in Fig. l, the putt ot the conduit indicated at cl is of the same or approximately the same cross sectioral area as the part at g, and in all cases tlc construction is such that the sound waves, while being rctlccted in straight lines from one part ol the conduit to the other, are never deflected in zig-zag lines against the side walls of the conduit, are never compressed by being passed through r=,-strieted parts thereof. nor

I I c. the corners /z being lcl't on the tube 9 to is the conduit so enlarged at the angles of i the bends as to diffuse the sound waves unduly while they are having their directions changed by the reflectors.

It will be understood that the invention is applicable generally to sound conduits having a bend or bends or meeting at an angle, but in all cases the construction must be such that the smallest area at the bend, bounded by the tubes and the reflector. is about equal to the sectional area of the tube from which the sound is Proceeding.

I claim as my invention l. A sound conducting pipe, having a bend provided with a plane or flat reflecting surface inclined equally to the axes of both parts of the pipe on opposite sides of the bend so that the sound waves are reflected in straightdines parallel with the axis of the pipe, the free space or cross sectional area at the narrowest place between the angle of the bend and the reflector being approximately equal to the cross sectional area of that part of the pipe from which the sound waves pass on their way to the bend.

2. A sound conducting pipe, having a r bend provided with a plane or flat reflecting surface inclined equally to the axes of both parts ofthe pipe on opposite sides of the bend so that the sound waves are reflected in straight lines parallel with the axis of the pipe, the parts of the pipe on opposite sides of the bend being of diflerent diameters and the free space or cross sectional area at the narrowest place between the angle of the bend and the reflector being approximately equal to the diameteror cross sectional area of thevsmaller part of the pipe from which the sound waves pass (in their way to the bend and such reflecting surface inclined equally to the axes of both parts of the pipe on opposite sides of the bend so that the sound waves are reflected in straight lines parallel with the axis of the pipe, the free space or cross sectional area at the narrowest place between the angle of the bend and the reflector -being approximately equal to the cross sectional area of that part of the pipe from which the sound waves pass on their way to the bend.

4. A sound conducting pipe having a plurality of bends, each bend being provided with a plane or flat reflecting surface inclined equally to the axes of both parts of the pipe on opposite sides of the bend so that the sound waves are reflected in straight lines parallel with the axis of the pipe, the parts of the pipe on opposite sides of the bend being of different diameters and the free space or cross sectional area at the narrowest place between the angle of the bend and the reflector being approximately equal to the diameter or cross sectional area of the smaller part of the pipe from which the sound wavespass on their way to the bend, and such reflecting surface being of such dimensions as to'receive all of the projected area from that part of the pipe from which the sound waves proceed.

In testimony whereof, I aflix my signature in presence of two witnesses.

- ALEX FISCHER.

Witnesses:

' A. E. VroAn' L. SIMIN p. 

